Reliance on GNSS is now commonplace. However, all GNSS systems share a common vulnerability: their signals are very weak. GNSS satellites operate from Mid-Earth Orbit (MEO), approximately 20,000-25,000 km above the earth, to provide the best coverage and geometry for triangulation. As such, the transmitted signal is extremely weak upon arrival at the surface of the earth – so weak that it is weaker than the surrounding radio noise. Special signal processing techniques recover the GNSS signal from the background noise, but the weak signal strength at the user’s receivers makes GNSS navigation very susceptible to interference.